Cr(VI) Oxidation Using Benzimidazolium Fluorochromate: Kinetics and Mechanism of the Oxidation of Some Diols
DOI:
https://doi.org/10.22159/ijcr.2026v10i4.381Keywords:
Diols, Benzimidazoliumfluorochromate, Kinetics, Oxidation, Correlation, MechanismAbstract
Objective: To investigate the kinetics and mechanism of the oxidation of four vicinal diols, four non-vicinal diols, and one monoether by benzimidazolium fluorochromate (BIFC) in dimethyl sulfoxide medium.
Methods: The oxidation reactions were studied under pseudo-first-order conditions using spectrophotometric monitoring of BIFC. Product analysis, kinetic measurements, deuterium isotope effect studies, and structure–reactivity correlations were employed to elucidate the reaction mechanism.
Results: Vicinal diols underwent glycol-bond fission to form carbonyl products, whereas non-vicinal diols and the monoether yielded hydroxycarbonyl compounds. The reaction showed first-order dependence on BIFC and Michaelis–Menten-type kinetics with respect to the substrate. A significant kinetic isotope effect and Taft correlation indicated α-C–H bond cleavage and the development of an electron-deficient transition state in the rate-determining step.
Conclusion: The oxidation proceeds through the formation of a substrate–BIFC complex followed by a hydride-transfer process. Vicinal diols undergo oxidation via a mechanism involving glycol-bond fission, whereas non-vicinal diols are converted into the corresponding hydroxycarbonyl compounds. The kinetic and mechanistic results provide strong support for the proposed reaction pathways and the role of substrate structure in determining reactivity.
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